It is desirable, especially with small scale dispersed photofinishing equipment or stand-alone equipment to reduce the heat consumption of the photographic processing machine. The benefit for the owner is lower operating costs and hence more profit per roll of film processed. Many processing machines in the marketplace today from large photofinishing machines to small microlabs have power saving features. The most prevalent is a standby mode for overnight periods, and periods of non-use. In this mode the chemical tank heaters are either switched off or operated at a lower temperature so that the tank can be returned to the processing temperature more quickly.
Heat from some sources within processing machines has been used to help perform other tasks within the machine. For example, a processing machine has been described in which at least one part of the heating section of a heat pump is utilized as a hot blower heating source of the drying section of the apparatus (JP 3266840A).
JP 9258405A describes an automated photographic processing apparatus in which waste liquid is evaporated and concentrated. Part of the heating air of a drying section is blown into the evaporator to accelerate the evaporation of the waste liquid.
U.S. Pat. No. 3,995,298 describes a photographic processing apparatus in which waste processing solutions are heated to evaporate them, the evaporated steam is condensed, providing heat to assist the drying of the photographic materials.
Despite these methods of saving heat, there remains the need to improve the recovery and reuse of heat by photographic processing machines. For example, heat that can be useful for photographic processing is often lost from several sources in the machine.
This invention describes processing machine designs that improve the recovery and reuse of heat by the machines where loss of heat from the processing machine is minimized.